The invention relates to apparatus for applying and controlling electrical stimulus to accomplish aversive/motivational conditioning/training of animals.
The state of the art in the use of electronic stimulus collars for dog training is comprehensively set forth in "Retriever Training", by Jim and Phyllis Dobbs and Alice Woodyard, 1993, "Understanding Electronic Dog-Training" by Dr. Daniel F. Tortora, 1982, and "Teaching Dogs the Skill of Silence", 1985, all published by the present assignee Tri-Tronics, Inc. The state of the art also is indicated in "Three-Action Introduction" published by Tri-Tronics, Inc., 1993 and "Solving Dog Behavior Problems with The Tri-Tronics Remote Trainer" published by Tri-Tronics, 1992, and U.S. Pat. Nos. 5,193,484 and 4,802,482, both owned by the present assignee. Upon information and belief, one defunct company, Ability Center, Inc. of Tucson, Ariz., has used an external resistor encapsulated between two washer-like metal surfaces mounted under and in series connection with one of the two usual electrodes of an electronic stimulus collar. We are aware of no prior electrical stimulus training devices that have included a stimulation current limiting resistor as an integral part of an electrode structure.
Various electronic stimulus collars, such as Tri-Tronics models 100, 200, 300 and 500, are commonly used for training dogs. Mostly as a result of efforts by Tri-Tronics, Inc. during the past ten to fifteen years, humane societies throughout the United States have come to recognize that proper use of such electronic collars is a very effective, efficient, and humane way to train or control dogs for a variety of purposes, such as general obedience, performance trials, hunting, herding, and police work. Electronic collars also have been used in "invisible fence" dog containment systems. To be most effective and humane, it is essential that electronic stimulus collars be able to reliably and consistently apply the intended degree of stimulus to the skins of a wide variety of dogs under a wide variety of conditions. (Although dogs are mentioned in most examples herein and in the above patents, it is recognized that electronic stimulus collars and the like also are effective in the training of other animals such as monkeys, horses, etc.)
Accomplishment of the foregoing is complicated by the fact that various dogs have greatly varying lengths and thicknesses of fur. Furthermore, their skin and fur conditions can range from very dry (since dogs do not perspire) and electrically nonconductive to very wet and highly conductive. The fur of a dog running through wet brush or jumping into a pond or creek, for example, during retrieval training, may be electrically nonconductive during the early part of a training procedure and very conductive during a later part thereof. Furthermore, some dogs may be very sensitive to electrical stimulation and require only a low level of aversive or motivational stimulation, while other dogs (especially if they are in a highly distracted state, for example, because they see another dog, a cat, rabbit, etc.) may be insensitive to or oblivious even to quite high levels of stimulation.
It should be helpful to now refer to FIGS. 2, 2A, and 2B, which show the structure of a typical prior art electronic stimulus collar 1. Electronic stimulus collar 1 includes a receiver unit 2, which may include conventional radio frequency receiver circuitry to receive RF signals from a remote transmitter device via the illustrated antenna. Receiver unit 2 also may include circuitry for decoding the demodulated RF signal to control stimulus generating circuitry. For a "bark control" collar, receiver unit 2 may receive audio or vibration signals from a microphone or transducer attached or connected to the receiver unit 2 or the collar. In any event, circuitry included in receiver unit 2 produces an appropriate electrical stimulus by means of a pair of spaced electrodes 6 and 7, which may be attached directly to the housing of receiver unit 2 as shown in FIG. 2, or may be attached to the inside surface of collar 10 and electrically connected to the circuitry in receiver unit 2 by means of insulated high voltage wires running along or within collar strap 10 to the secondary terminals of an output transformer or other circuitry or means for generating high voltages within receiver unit 2.
The level of stimulus produced between electrodes 6 and 7 while they are making effective electrical contact to the skin of the dog needs to be selected to suitably match the present sensitivity of the dog and the present type of training (eg., learning, motivational, or aversive training).
To achieve such matching, electronic stimulus collar 1 of FIG. 2 also includes a pair of banana plug jacks 11 and 12, into which a plug-in resistor element 14 is plugged, shown in FIG. 2A. Plug-in resistor element 24 includes two gold plated banana plugs 15 and 16 which are inserted into and make reliable electrical contact with gold plated conductors of jacks 11 and 12. Typically, Tri-Tronics electronic stimulus collars have been sold with a kit of five such plug-in resistor elements, with suitable values of resistance 17 being connected between banana plugs 15 and 16 when plug-in resistor element 14 is plugged into jacks 11 and 12. The resistance 17 is thereby connected in series between one of the terminals of a secondary winding of an output transformer in receiver unit 2 and one of the electrodes 6 or 7. Typically, the five plug-in resistor elements 14 may have values of resistance 17 of one megohm, 330 kilohms, 100 kilohms, 33 kilohms, and zero ohms.
When electrodes 6 and 7 then make electrical contact to the dog's skin (by virtue of both the high open circuit transformer output voltage between them and their close proximity and/or physical contact with the skin), a voltage generally proportional to resistance 17 is developed across resistance 17. This regulates current flow (which constitutes the desired electrical stimulus) through the dog's skin between the two points at which probes 6 and 7 electrically contact the skin. For plug in resistor elements with non-zero resistance, the magnitude of the current, and hence the level of the electrical stimulus, is limited by the selected value of the resistance 17. In any case, the electrical stimulus is applied to the skin of the dog between the two electrodes 6 and 7. If a zero resistance plug-in element 14 is plugged into jacks 11 and 12, nearly all of the energy produced by the output transformer is applied as a stimulus to the skin of the dog. Thus, by selecting the plug-in element with an appropriate resistance value, a suitable level of stimulus intensity will be applied to the dog's skin.
It is well known that the degree of electrical stimulation which is most effective in a particular training situation is dependent upon the attentiveness of the dog to the trainer. Ordinarily, relatively low levels of electrical stimulation selected by the trainer in accordance with good dog training practice are very effective in accomplishing desired training goals. However, if the dog is distracted, for example, by a rabbit or cat running nearby, a much higher degree of electrical stimulation may be required to achieve an appropriate response by the dog. But, it also is known that an inappropriately excessive stimulus may confuse the dog.
Failure to deliver appropriate stimulus at precisely the correct time in a dog training situation can result in a confused, poorly trained animal, and in fact often reverses previous training accomplishments. Consequently, the reliability of "delivering" the intended electrical stimulus level to the skin of the dog under a wide variety of conditions (eg., of collar tightness, thickness and wetness of fur, general sensitivity of the particular dog to electrical stimulus, and the presence of distracting influences or occurrences) is quite critical to the overall effectiveness of electronic stimulus collars and the associated training techniques.
Electronic stimulus collars of the type shown in FIG. 2, sold with plug-in series resistive elements to control the level of electrical stimulation applied to the dog, have been quite effective and are widely used by trainers. However, the physical size and weight of some known electronic stimulus collars, for example, Tri-Tronics' models 100, 200 and 500, is such that they are too large and heavy for smaller dogs (for example, a toy poodle). Nevertheless, such smaller dogs also could benefit greatly from aversive or motivational stimulus training techniques using electronic stimulus collars. Also, the cost of suitable plug-in elements 14 as a method of varying stimulation intensity is comparatively high.
Furthermore, plug-in resistor elements 14 are physically large, and this requires the physical size of the receiver unit 2 to be larger than desirable in order to accommodate the necessary jacks. Also, such plug-in resistor elements 14 occasionally become snagged by brush, dislodged, and lost as the dog runs through the brush. Professional trainers may have to frequently remove and insert various plug-in resistor elements 14 when training a large number of dogs using only one electronic stimulus collar. This wears through the gold plating on the banana plugs and weakens spring elements of the banana plugs. Consequently, electrical contact becomes unreliable and stimulus delivery may become sporadic, thereby necessitating the inconvenience and cost of purchasing replacement plug-in elements 14.
A typical prior art training procedure using a remote transmitter of the type which can apply three remotely selectable levels of stimulus by depressing buttons to produce stimulation pulses at different pulse rates is described next. For a particular dog on which an electronic stimulus collar is being used for the first time, the highest resistance plug-in element 14 is plugged into banana plug jacks 11 and 12. The lowest level button on the transmitter unit is actuated so that the lowest level stimulation signal is applied to the neck of the dog. If the dog does not appear to have noticed the stimulation (for example, the dog does not change head position or ear posture, cock its head, or exhibit an involuntary muscle twitch), a higher stimulation level is selected by removing the present plug-in element 14 and replacing it by the next lower resistance value plug-in element. The above process is repeated until a "threshold" stimulus level is established for that dog, as evidenced by one of the above reactions. With the installed plug-in element selected in this manner, training of the dog can proceed. Stimulus intensity thereafter is varied in noticeable increments by depressing the various intensity controls on the remote transmitter. The foregoing procedure thus establishes a threshold stimulus level which can result in very effective "motivational" stimulus training for a particular dog. After the dog has become accustomed to the electronic stimulus collar, other plug-in resistor elements 24 which allow higher levels of stimulus to be applied then can be used effectively. Higher levels of stimulus can be used for motivational training or for aversive training to deter the dog from continuing an undesirable behavior.
As indicated above, it is well known that unreliable operation of electronic stimulus collars can "undo" previous accomplishments in the training effort. Furthermore, if the equipment fails to deliver a strong aversive stimulus when the dog embarks upon action which he previously has been trained to avoid, an effective training opportunity would be lost.
The opposite situation also can occur if the dog accidentally receives an extremely high intensity of stimulus at a time when it is not intended. For example, if it is raining or if the dog has recently jumped into a pond so that moisture has "shunted" or partially short-circuited a 1 megohm resistance 17 in a plug-in resistive element 14, and the dog then begins creeping forward when he is "on point" (i.e., standing motionless upon detecting the scent of a game bird), and if the trainer then applies what is intended to be a gentle stimulus to remind the dog to not creep forward, a very excessive stimulus may be applied to dog as a result of such shunting. The dog then is likely to associate the scent of the game bird with the excessive stimulus, making it very difficult for the dog to exhibit the desired instinctive pointing behavior in the future.
Thus, various conditions are known to cause inconsistent application of the desired stimulus to the dog. Most of the conditions which result in such inconsistent application of electrical stimulus to the skin of the dog are directly related to how consistently the levels of desired stimulus current are applied by electrodes 6 and 7 to the dog's skin under a variety of conditions, ranging from loose collars and short, dry fur or dry skin to long, shaggy, wet, conductive fur or wet skin.
Despite many years of effort and advancement in the area of effectively applying the stimulus produced between the output terminals of the secondary winding of the output transformer of the receiver unit to the skin of the dog, there still remains an unmet need for a simple, more compact, effective, inexpensive, and especially a more consistent way of delivering a desired level of electrical stimulus to the animal being trained.